This invention relates generally to a method and apparatus for gas burners, and, more particularly, a method and apparatus for improved flow characteristics for gas surface burners used in a gas-cooking product.
Atmospheric gas burners are commonly used as surface units in household gas cooking appliances. A significant factor in the performance of gas burners is their ability to withstand airflow disturbances from the surroundings, such as room drafts, rapid movement of cabinet doors, and oven door manipulation. Manipulation of the oven door is particularly troublesome because rapid openings and closings of the oven door often produce respective under-pressure and over-pressure conditions under the cook top.
Gas surface burners used in cooking products typically include a burner body including a plurality of burner ports through which a gas is distributed, and a burner cap positioned over the burner body. Almost all designs include an internal chamber of increased gas volume near the burner ports. This is important where gas flow may change over time. Providing equal flame characteristics from one port to the next is critical to prevent hot spots or uneven heating of the cooking vessels. Variations in the size of the burner port and the distance of the burner port from the venturi can also affect the flame characteristics. Adverse changes in the flame characteristic are detrimental to various performance characteristics such as inability to support flames at certain ports particularly at very low gas input rates. Gas refers to any gas or fuel air mixture.
A larger port exhibits higher flow rates than smaller ports in the same burner for a given input flow. Thus, port sizing, a static attribute of a burner, often determines the flow characteristics of a particular burner at a specific flow. This defines the distribution of flow rates across the burner ports. In some cases, it is desired that the flow characteristics be “Dynamic” or variable. One such instance would be in a burner where the flow characteristics for a region of ports are altered during high flow and unaltered during low flow conditions. For example, where the port designs are optimized for low flow, the ports produce poor and undesirable operational conditions during high flow. This is particularly evident in multiple ring burner assemblies or burners having multiple flame rings.